The invention relates to a brake application mechanism for a brake, particularly for a sliding-caliper disc brake having an application shaft which extends parallel to the plane of the brake disc. More particularly, the invention relates to such a mechanism wherein on the side of the shaft which faces the brake disc the shaft is supported against a thrust piece which is movable against the brake disc by a circularly arcuate first contour which is rotatably mounted in a suitable bearing seat, and on the side of the shaft which faces away from the brake disc, the shaft is supported against an element with respect to which the thrust piece is movable by a second contour which is eccentric with respect to the first contour.
An application device of the type described above is known from German Patent Document OS 40 32 885 A1. The first contour and the bearing in the device engage each other such that the application shaft can serve simultaneously as the bearing means for the thrust piece, thereby obviating bearing and guide means for the thrust piece. The second contour in the known device is in the form of a circular arc. Because the two circular arcs, namely that of the first contour and that of the second contour, are mutually eccentric, when the application shaft is rotated the thrust piece executes a tilting movement in a plane perpendicular to the axis of the brake disc.
An angular attitude of the thrust piece results, so that when the brake is actuated the brake shoe assumes a corresponding angular attitude, with deleterious effects on the braking process as well as uneven wear on the brake linings.
In the known application devices disclosed in German Patent 26 14 321 C2, European Patent 0 291 073 B1, and German Patent OS 34 11 74b A1, the application shaft on the one side and thrust piece on the other side are respectively decoupled by suitable means, to avoid tilting of the thrust piece. The decoupling is accomplished by a sphere, a transversely movable plate, or a thrust rod between the application shaft and the thrust piece. However, a result of the decoupling is that the application shaft and thrust piece cannot be held together and guided together, which necessitates flexible holding means for the application shaft in the cited application devices according to the state of the art; e.g., the spring 86 in German Patent 26 14 321 C2. The decoupling renders the position of the application shaft unstable, and as a result the brake application process is uneven.